SU1411659A1 - Method and apparatus for determining defective articles - Google Patents

Abstract

The invention relates to a measuring and control technique and can be used to detect defective foam products. The purpose of the invention is to increase the information content and reliability of the determination of defects in foam products after annealing by eliminating single impulse noise. Using the integrator 6, the background level of the intensity of the incoming signals is estimated, by annealing the foam, a stress-strain state is created in it and the increment of the intensity of the acoustic emission signals relative to the background level is measured. At the output of the summing counter 4, the value of the integral of the increment of the intensity of the acoustic emission signals is null. According to KL OOM, the area formed by the detector is judged. or cleavage in the material of the product. 2 sec. item f-ly, 1 ill. iO (L

Description

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The invention relates to the instrumentation 1 technician and can be used to detect defective foam products.

The aim of the invention is to increase the information content and reliability of detection of defective foam products from jla by eliminating single impulse interferences.

Figure 1 shows a block diagram of a device for implementing a method for determining defective products.

A device for determining defective products contains a receiver 1 of acoustic emission signals and a series-connected constant-voltage source 2, a key 3, a counter 4 and an indicator 5 connected to the output of the receiver 1 of acoustic emission signals, an integrator 6 connected to the output of the last N comparators 7 and 8 and the shaper 9 discrete levels of direct voltage, N outputs of which are connected to the second inputs of the respective comparators 7 and 8, connected to the outputs of the latter decoder 10, are connected in series 11 pulse generator and frequency divider 12, the OR 13 element, the output of which is connected to the second input of counter 4, and N elements 14 and 15, the first inputs of which are connected to the corresponding frequency, the frequency divider 12 outputs to them, the second inputs to the corresponding, to them the outputs of the decoder 10, and the outputs - to the corresponding entry of the element OR 13.

The essence of the method for determining defective products is that the material of the product is loaded, the intensity of the acoustic emission signals is measured in the material of the product, which is used to judge the presence of defects in the products. Before loading the material of the product, the background level of the intensity of acoustic emission signals is measured in it, the material is loaded by annealing method, creating a stress-strain state in it, and the intensity of the acoustic emission signals relative to the background intensity value is measured, and The area of the resulting defect (crack or cleaved) is judged by the integral of the increment of the acoustic emission signals.

At the end of the annealing of the monitored product after leveling the temperatures at a technology-defined point in time, the receiver 1 of acoustic emission signals is brought into mechanical contact. Then, the key 3 is closed. A voltage is applied to the first input of the counter 4, under the influence of which the counter is zeroed. The device is ready for operation.

Even with the control of a known good product due to transients in it after otzh: ha, signals are received at the input of receiver 1 of the signals of the acoustic mission

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acoustic emission, which in the form of sporadically occurring voltage pulses of varying shape, amplitudes and durations from the output of receiver 1 are transmitted to the input of integrator 6. This integrator forms an analog voltage based on the input signal, the value of which is proportional to the current intensity of the signal flux at the input of receiver 1 acoustic emission signals. The voltage from the output of the integrator 6 is fed to the input of the imaging unit 9 and to the first inputs of the comparators group 7 and B. The output voltage of the first of the N outputs of the imaging unit 9 is equal to the output voltage of the integrator 6. The voltage on the other outputs of the imaging unit 9 increases from the previous to the next by some given constant value. Since these voltages are applied to the second inputs of the comparators 7 and 8, when the intensity of the acoustic emission signals is lower than the background, the inhibitory potentials are set at the outputs of all the comparators 7 and 8. As the flow of acoustic emission signals increases, a higher resolution background potential initially appears at the output of the first comparator 7, since only at its first input is the voltage higher than the voltage at the second input. Then, as the voltage of the integrator 6 rises further, the resolving potential appears at the output of the second comparator (not shown) in the group of N comparators 7 and 8, etc.

Since the output voltages of the comparators 7 and 8 are applied to the inputs of the decimator 10, a resolving potential appears at one of its outputs, depending on the combination of the permitting potentials at the inputs of the decimator 10. This potential opens one of the elements AND 14 and 15. The first inputs of each of the elements 14 and 15 are supplied with a pulse voltage of the corresponding frequency. These voltages are generated using a frequency divider 12 and a generator 11. Moreover, the more comparators 7 and 8 have resolving potentials at their outputs, i.e., the greater the intensity of the flow of acoustic emission signals, the higher the frequency the pulse voltage passes through the opening element And 14 and 15. The outputs of all elements And 14 and 15 through the element OR 13 are connected to the second, summing, the input of the counter 4. Thus, the greater the intensity of the flow of acoustic emission signals, the higher the frequency pulse The current is fed to the summing input of counter 4, the greater the speed of the summation. With a change in the intensity of the input stream of acoustic emission signals, the counting rate changes, increasing or decreasing with increasing LI or decreasing, respectively, the intensity of the flow of acoustic emission signals. This thereby integrates over time the increments of the intensity of the flow of acoustic emission signals compared to the background level of intensity.

At the end of the transient processes in the controlled product, according to the indications of indicator 5, the suitability of this product is evaluated.

Claims (2)

Invention Formula . The method of determining defective products, which consists in loading the material of the product, measures the intensity of the acoustic emission signals, according to which the presence of Defects in the product is judged. characterized in that, in order to increase the information content and accuracy of the determination of defects in foam products, the background level is measured before loading the material of the product, the intensity of the acoustic emission signals is loaded by annealing, and the increment of the intensity of the acoustic emission signals is measured 0 relative to the background level of intensity, and the area of the defect formed is judged by the integral of the increment of the intensity of the acoustic emission signals. 2. A device for detecting defective products, comprising an acoustic emission receiver and a series-connected DC voltage source, a key, a counter and an indicator, characterized in that it is equipped by an integrator connected to the output of the acoustic emission signals by N comparators and shaper discrete levels of constant voltage, N outputs of which are connected to the second inputs of the corresponding comparators connected to the outputs of the latter decoder, p subsequently connected by a pulse generator and a frequency divider by an OR element whose output is connected to the second input of the counter, and N elements AND whose first inputs are connected to the corresponding outputs of the frequency divider, the second inputs to the corresponding outputs of the decoder, and the outputs to the corresponding inputs element or. five